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Ghost in the machine
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I was just watching a YouTube vid on the Duke 5 piston rotary concept engine being designed for possible use in future motorcycles. Has anyone else seen this? Thoughts...

Sorry I'm computer illiterate and can't post links or images.

I like the idea, it reminds me of a much more complicated version of the old Wankel rotary used by Suzuki and Arctic Cat. But I keep thinking what would an internal failure look like?

I also think there may be an issue with the rotational force of an axial motor possibly causing unwanted gyroscopic lean on a MC.

I like the idea that the future may hold more options than just electric though.
 

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Premium Member
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NZ Duke axial.

Article about it is in the January 015 Motor Cyclist mag.
Looks interesting. Advantage at the moment is light weight and smoothness.
Also in the mag is an article on the Ducati variable timing, and the Scrambler, which has a base price of $8,485.00.

Unkle Crusty*
 

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Ghost in the machine
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Yeah, it reminded me of a revolver cylinder on top of a carnival Tilt-A-Whirl.
 

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If you follow the description carefully you will see it is basically a piston port 2 stroke engine. It looks different mostly because they chose to move the cylinders past the ports and spark plug.
 

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I don't believe that is 2 stroke, however, yes it is a piston engine.

Rotary is a bad word to put on it because it is nothing like a rotary engine.
 

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Gone.
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If you follow the description carefully you will see it is basically a piston port 2 stroke engine. It looks different mostly because they chose to move the cylinders past the ports and spark plug.
Each piston has four strokes: Intake, Compression, Power, and Exhaust. It uses ports, yes, but there's no way it could be confused with a 2-stroke engine.

I think it's a very innovative concept, but I'd love to see more details.
 

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Greatest Member Ever
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Can someone please post a link to something that will clue me in to what ya'll are talking about??? I really am a busy sort of guy, and google sounds like a lot of work... Would greatly appreciate an accurate link...
 

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Aging & Worn
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Some impressions:

A. The overall size of the motor doesn't seem THAT much more
compact than a V6 (visual first impression)

B. I see less spark plugs and wonder, why "three" as opposed to "two"
(let's say)

C. Less emissions and more power? Interesting!

D. If they are going to "re-invent the wheel," why not change the size
and shape of the PISTONS, while they're at it?!

E. Less parts, but the ones that ARE there, are moving a HECK of a lot
more, making me think there is more potential for wear or break down.
That Reciprocator (sp?) gear is the FIRST one I'd expect to break down.

F. All they've REALLY done, is re-invent the Crankshaft in a different form.

G. Based on the orientation shown, they have embraced the idea of the
horizontal stroke motion (like the Subaru motor) which makes sense.

H. "No exhaust valves present." No exhaust pipes needed? No exhaust?
huh??

-Soupy
 

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Wow that thing is a brilliant design! I wonder though, will it survive "durability testing" that has often been a weak link with other interesting concepts too.

Personally I do consider that a "2 stroke" format despite the ports being located in a weird location. Does that engine have crankcase oil or doesn't it? I guess it probably does, and that does tend to steer the design 'away' from typical 2-stroke engines, as they usually use pre-mix oil to survive operation.

2-stroke engines have always been 'simpler' and higher powered than 2-strokes, but they are horrible in pollution. How did these guys fix that?

.. just thinking about it now, maybe the elimination of pre-mix oil but keeping the 2-stoke configuration was the key?

Something else to think about... they could technically double the size of that engine by pointing another bank of pistons in the opposite direction, sharing a common "crankshaft" or whatever you call that thing.
 

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If it has pistons, it is not a Wankle/ rotary engine.

Rotary engines are not new at all to motorcycles, Norton and Suzuki attempts come to mind.

I like 2 stroke engines for their simplicity and if set up right, their reliability.

The Suzuki 750, 3 cylinder, 2 stroke, "Water buffalo" was a great bike and fun to ride. The 500 and 750cc Kawasaki, 3 cylinder, 2 stroke bikes were "Earth shattering" at the time:biggrin:

My concern is would Vance & Hines build an exhaust that would make these new innovative engines sound like a REAL motorcycle??? (HD):icon_cool:

Sam:coffeescreen:
 

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Again it is not a 2-stroke.

a. possibly, hard to tell the size of something in the movie picture show without a size standard present

b. 3 spark plugs because in 1 revolution of the engine each piston fires 3 times, at the end of each compression stroke the piston has moved to another location inside the engine, thus 3 intakes, 3 sparks, 3 exhausts

c. not sure about it having less emissions, however it should have more power.......in reality it is a 15 cylinder engine

d. ???

e. I would expect the head to be having problems, head does not move, cyclinders move, and that is the hot spot.

f. Wrong, but for fun lets say that is a correct statement, could you have thought it up?? I say no, because you didn't. I don't think I would try to simplify what they have done with an "all they've done" statement.

g. I don't know anything about the Subaru, but VW had horizontal stroke a long time. This engine looks to me like it can be situated in any direction they want, of course the lubricating system has yet to be seen.

h. True there are no exhaust valves, also true there are no intake valves, they are ports(a hole in the head), adding pipes into the animation would not help in explaining how the engine works. But if you watch to the point where they show an actual engine in operation you will see the exhaust pipes.
 

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Ahh OK yes you're right, that engine does have a 4-stroke cycle. Soo much going on simultaneously to catch all the detail!

It's an intriguing design. If I understand it correctly, from the pistons point of view (if you stick a camera looking 'up' from the piston) you would see the "cylinder head" constantly rotating above you, exposing the various valves & spark plug as needed. Correct?

So I wonder how they avoided any cylinder head sealing issues? Especially in long term operation, and especially during the "power stroke"
 

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My concern is would Vance & Hines build an exhaust that would make these new innovative engines sound like a REAL motorcycle??? (HD):icon_cool:

Sam:coffeescreen:
V&H will build an exhaust for almost anything you can think of. Seriously. Call 'em sometime. They're like, exhaust pushers or something. Lol.
 

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Ahh OK yes you're right, that engine does have a 4-stroke cycle. Soo much going on simultaneously to catch all the detail!

It's an intriguing design. If I understand it correctly, from the pistons point of view (if you stick a camera looking 'up' from the piston) you would see the "cylinder head" constantly rotating above you, exposing the various valves & spark plug as needed. Correct?

So I wonder how they avoided any cylinder head sealing issues? Especially in long term operation, and especially during the "power stroke"
I have revisited several times now. I missed the 4 stroke aspect the first time through but now agree it is a 4 stroke. The plugs do indeed rotate into view at the head but the ports, intake and exhaust, are exposed at a different location if I am interpreting what they say correctly. I probably need to view it at least once more to truly understand what is going on.
Size is not an issue. If you have a solid design you can scale up or down to get a 100 cc or 2000 cc equivalent displacement. I'm not even sure how you would measure displacement. Is it the volume displaced by the piston in a single cycle times 3 or the displacement by all 5 cylinders in a full crank rotation?
You could build that engine design to run a model airplane. Size is meaningless without a reference.
 

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Oh boy

2 or 4 stroke is determined by how many strokes the piston travels before the plug fires.
Where the port holes are does not matter.

The swept volume is the area measured when the piston is at BDC, bottom dead center, to the top of its stroke.
Compression is the ratio of the swept volume, to the compressed volume, when the piston is at TDC, top dead center.
This explains why the compression ratio increases if you increase the bore size.

This engine has 5 cylinders of 200 cc each. Details are in the magazine I mentioned above.

Using crank revolutions per pistons firing, helps explain why multi cylinder engines gain a horse power advantage.
Example. Single 4 stroke, bang, count four, bang.
V8 4 stroke, bang bang bang bang, count one, bang bang bang bang, count two.
The Duke engine fires 3 times per revolution.
125 hp, 88 torque. Motor weighs 86 pounds.

Unkle Crusty*
 
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